Employing Arthrospira platensis biomass and compost to immobilize Cd in soil and enhance plant mineral nutrition
摘要
The accumulation of Cd in agricultural soils poses a significant threat to food safety and environmental sustainability. This study investigates the effectiveness of Arthrospira platensis biomass, applied individually or in combination with compost, in reducing Cd bioavailability and enhancing plant mineral nutrition. Soil was collected from a cocoa crop with a Cd concentration of 3.72 ± 0.20 mg kg⁻1. A greenhouse trial was conducted, where A. platensis biomass was applied individually or in combination with compost at doses ranging from 2 to 4% w/w. After 90 days changes in soil physicochemical properties and Cd bioavailability were assessed through geochemical fractionation. The results demonstrated a substantial decrease in the bioavailable fraction, with reductions of 1.5-, 1.7-, 1.9-, and 2.1-fold, respectively. Concurrently, the Cd concentration associated with reducible, oxidizable, and residual fractions increased significantly, indicating a shift towards more stable and less bioavailable forms. Additionally, nutrient analysis revealed enhanced N, P, and K concentrations in plant shoots, with increases ranging from 0.39- to 0.84-fold, depending on the treatment. These findings suggest that the application of A. platensis biomass, particularly in combination with compost, can mitigate Cd bioavailability while enhancing soil nutrient composition. This study presents a promising strategy for reducing heavy metal uptake in crops and improving soil health in contaminated agricultural lands.